3:30 PM - SM01.10.05
Long-Term Biological Influence to Heart by Soft Ferroelectric Polymer Designed as Life-Long Cardiac Energy Harvester
Jun Li1,Hao Wei1,Timothy Hacker2,Weibo Cai1,Xudong Wang1
University of Wisconsin-Madison1,University of Wisconsin–Madison2
Since the first clinical implantation of pacemaker in 1958, the cardiac implantable medical devices have experienced a rapid evolution. While increasing population benefits from these technologies, the device-related complications such as infection, lead and battery failure are not negligible. Especially the rigid and weighty battery, not only malfunction may occur with battery depletion, but also the replacement of or recharging the batteries requires substantial surgical or technical efforts, introducing additional suffering and complexity to the patients. Therefore, the batteryless devices are on the horizon as a coming paradigm shift. To date, self-powered pacemaker and defibrillator based on triboelectric, piezoelectric and electromagnetic-induction has been proposed and demonstrated. While the feasibility of self-powered cardiac pacing has been well present, few of studies focused on the biological influence these devices caused to heart and the long-term stability of implants, which are essential to the practical applications. To address this critical issue, we present a systematic study of a cardiac energy harvester based on the ferroelectric polymer, polyvinylidene fluoride (PVDF), implanted on the left ventricle of three swine hearts for up to two months with consistent operation.
A PVDF patch with biomimetic mechanical property wire was first designed. The packaged PVDF harvester had a stable in vivo output around 1.5 V when implanted between pericardium and heart of swine. Afterwards, an up-to-two-months in vivo output of this cardiac energy harvester was recorded with device consistently operating, which exhibited a constant output from the 3 days post implantation. Meanwhile, multiple techniques, including completed blood count, cardiac enzymes test, echocardiogram, electrocardiography, as well as pressure–volume loop were used to evaluate the function of heart with implanted energy harvester. While the whole functions of heart kept normal evidenced by these techniques, no signs of toxicity or incompatibility were found from the surrounding tissues of device based on complete pathological analyses. Moreover, devices exhibited high sensitivity with stable electrical output conveying information regarding heart activity during the entire examine period and packages were also able to effectively insulate the i-NG in biological environment.
These series of in-vivo and in-vitro studies confirmed the high biological feasibility of using i-NG in vivo for cardiac energy harvesting, and thereby further enables batteryless cardiac pacing and monitoring. This research provided the first cornerstone for the future intelligent self-powered cardiac system implantation.
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